1. Field of the Invention
The present invention relates to a pinion gear for a dual-bearing reel, particularly to a pinion gear that is meshed with a drive gear configured to transmit rotation of a handle to a spool and is configured to function as a clutch control mechanism by moving in a spool shaft direction. Further, the present invention relates to a dual-bearing reel including the pinion gear.
2. Background Information
In a dual-bearing reel, a pinion gear functions as a clutch control mechanism as described above and a rotation transmission mechanism (see Japan Laid-open Patent Application Publication No. JP-A-2009-82027). The clutch control mechanism is configured to be switched between a coupled state, transmitting rotation of a handle to a spool and a decoupled state, blocking transmission of the rotation. The clutch control mechanism is composed of a clutch pin and a tubular pinion gear. The clutch pin is mounted to a spool shaft. The pinion gear has a groove configured engage the clutch pin. On the other hand, the rotation transmission mechanism is configured to rotate the spool, while the pinion gear is meshed with a drive gear configured to be rotated in conjunction with the handle.
The pinion gear is mounted on the outer peripheral side of the spool shaft so as to be rotatable and axially movable. The pinion gear has two support parts on both axial ends thereof. The support parts are supported by bearings. Further, the pinion gear has a gear part in the center part thereof. The gear part is meshed with the drive gear. In other words, the gear part is disposed between the two support parts. The gear part is disposed at an interval from the support part disposed on a first end side (hereinafter referred to as a first support part), while being disposed adjacently to the support part disposed on a second end side (hereinafter referred to as a second support part). Yet further, the pinion gear has a clutch control part between the gear part and the first support part. The clutch control part enables a clutch plate to be engaged therewith.
The well-known pinion gear includes the clutch control part to be engaged with the clutch plate. The clutch control part has an annular groove shape and is disposed between the gear part and the bearing disposed on the one end side. In other words, the clutch control part is a narrowed part of the pinion gear.
In this type of pinion gear, the part between the gear part and an engaging part (including the groove) of the clutch mechanism, i.e., the narrowed part for transmitting power (torque) is thinly formed and has the smallest diameter Thus, the narrowed part is likely to be deformed (distorted or flexed). When the narrowed part is deformed, errors can be caused when meshing with the gear part. This may result in a deterioration in the gear feeling. Chances are that the tooth root of the gear part interferes with the narrowed part and this tendency becomes significant, especially, where the root circle diameter of the gear part is less than the outer diameter of the narrowed part.
Similarly, the second support part, disposed adjacently to the gear part, is also required to have a shape with a diameter less than the root circle diameter of the gear part in order to avoid interference with the tooth root of the gear part. When the second support part is thus structured, the pinion gear can be smoothly supported at the second support part during its rotation and a clutch action can be smoothly performed. The drive gear is herein meshed with the gear part, while the pinion gear is supported at both ends thereof, i.e., the first and second support parts. Hence, chances are that the narrowed part is significantly flexed where the narrowed part has a shape with a diameter less than that of the second support part.